Is urban pollution a menace
to urban agriculture?
Erik J Joner
Senior scientist, Bioforsk Soil & Environment
Ås, Norway
Er...
Overview
 About environmental pollutants
 Classification of soil and soil amendments
 Results from soil and plant analy...
About environmental pollutants
Anthracene (ANT)

Heavy metals
 Essential (Zn, Cu, Co)
 Non-essential (Pb, Cd, Ni, Cr, As...
Sources of pollution
Current:
 Combustion
• Transportation
• Domestic burning of firewood
• Waste incineration
 Sewage s...
How do pollutants get into plants?
Form soil (mostly)
 Metals
From air (a little bit)
 Metals and organic pollutants
 D...
Transfer from roots to shoots
HM

Strong barriers
 From soil to roots
 From roots to shoots
 Into seeds/pollen
Dilution...
Metal concentrations in soil
Arsenic

Cadmium

Chromium

Copper

Nickel

Lead

Zinc

39

6

Cobalt

85

36

35

11

117

H...
Upper limit for metals
in kindergarten soils
Plant analyses, 2012
Transfer from roots to shoots
Total vs. bioavailable metals
 Zn in soil: 120 mg/kg i 1 m2 -> 200 L = 500
kg: 60 g -> 1 ha...
Metals and PAH in honey
Cause for concern?
 Take home message: Urban agriculture is safe
 Very low levels in plants grown on clean soil
But:
 S...
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Oslo_Eric Joner

  1. 1. Is urban pollution a menace to urban agriculture? Erik J Joner Senior scientist, Bioforsk Soil & Environment Ås, Norway Erik.Joner@bioforsk.no
  2. 2. Overview  About environmental pollutants  Classification of soil and soil amendments  Results from soil and plant analyzes  Cause for concern?
  3. 3. About environmental pollutants Anthracene (ANT) Heavy metals  Essential (Zn, Cu, Co)  Non-essential (Pb, Cd, Ni, Cr, As, …) Chrysene (CHR) Organic pollutants (more or less degradable)      Polycyclic aromatic hydrocarbons (PAH) Halogenated (Cl, Br, F) compounds (e.g PCB) Phenols Pesticides Soot Dibenzo(a,h)anthracene (DBA) PAH, examples Biological contamination  Bacteria, fungi, viruses, protozoa Polychlorinated biphenyls (PCBs)
  4. 4. Sources of pollution Current:  Combustion • Transportation • Domestic burning of firewood • Waste incineration  Sewage sludge  Long range transport • Industry Past • Industry • Transportation (Pb) • Waste disposals • Naturally metal rich soils (Alun shales)
  5. 5. How do pollutants get into plants? Form soil (mostly)  Metals From air (a little bit)  Metals and organic pollutants  Disease (Mildew) From fertilizer/manure/watering  Human pathogens
  6. 6. Transfer from roots to shoots HM Strong barriers  From soil to roots  From roots to shoots  Into seeds/pollen Dilution effect  Well fertilized plants have smaller root systems and more edible parts HM
  7. 7. Metal concentrations in soil Arsenic Cadmium Chromium Copper Nickel Lead Zinc 39 6 Cobalt 85 36 35 11 117 Herligheten, Mineral produced soil, Oslo Organic 19 44 37 John Colletts plass, Outer 58 87 53 33 45 111 urban soil, Oslo Inner 38 94 36 38 34 120 Fokhol Low 19 1.8 10 45 48 55 21 143 bio-dynamic farm, Hedemark High 20 2.0 14 56 57 86 21 178 Means for arable Mean 5* 0.22 27 19 21 24 64 Norwegian soils Low 0.03 1 2 1 4 7 High 2 92 87 86 77 356  Urban soils are within the range of arable soils
  8. 8. Upper limit for metals in kindergarten soils
  9. 9. Plant analyses, 2012
  10. 10. Transfer from roots to shoots Total vs. bioavailable metals  Zn in soil: 120 mg/kg i 1 m2 -> 200 L = 500 kg: 60 g -> 1 ha: 600 kg  Zn in plants: 50 mg/kg -> 4000 kg barley/ha: 200 g Zn i harvested grain  0,03% taken up in edible parts
  11. 11. Metals and PAH in honey
  12. 12. Cause for concern?  Take home message: Urban agriculture is safe  Very low levels in plants grown on clean soil But:  Some soils in the city may be polluted by spills or old industry  If in doubt, consult EPA maps of polluted sites  Wash leafy plants and peel roots/tubers  How large proportion of your diet is from urban grown food?  Respiratory intake from city air is surpassing food intake

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